ui: update theme, add night mode support

Change-Id: Id7de59c49e45b0e914dae257b8f539537170300a
diff --git a/ring-android/app/src/main/res/layout/item_device.xml b/ring-android/app/src/main/res/layout/item_device.xml
index aa7c566..f1c6e15 100644
--- a/ring-android/app/src/main/res/layout/item_device.xml
+++ b/ring-android/app/src/main/res/layout/item_device.xml
@@ -27,7 +27,7 @@
         android:layout_height="wrap_content"
         android:layout_alignParentStart="true"
         android:layout_centerVertical="true"
-        app:srcCompat="@drawable/ic_desktop_windows_black" />
+        app:srcCompat="@drawable/baseline_desktop_windows_24" />
 
     <TextView
         android:id="@+id/txt_device_label"
@@ -77,8 +77,7 @@
         android:background="?selectableItemBackgroundBorderless"
         android:contentDescription="@string/account_device_revoke"
         android:padding="8dp"
-        android:tint="@color/black"
-        app:srcCompat="@drawable/ic_action_edit" />
+        app:srcCompat="@drawable/baseline_edit_24" />
 
     <ImageButton
         android:id="@+id/revoke_button"